The present invention is directed to an improved centering device for axial lead components and more particularly to a device for centering the bodies of varying lengths of successively presented components.
The above-referenced U.S. Pat. No. Re. 27,968 describes a machine constructed to feed tape-carried axial lead components to an insertion head which is adapted, in sequence: to adjust the head for reception of component bodies of various lengths; to sever the leads of a component in order to separate such component from a pair of spaced carrier tapes; to bend the severed leads at right angles to the axis of the separated component; and to drive the bent leads into preformed apertures provided in a circuit board disposed below the insertion head. The adjustment of the head for different body lengths is provided by variable spacing of two movable sections of the head through means of a lead screw having a pair of equally spaced and oppositely threaded screw portions, each of which is threadedly received in one of the sections, so that rotation of the lead screw in either direction will effect the spacing of the sections and thus the amount severed from the leads and the location of the bend in the unsevered portions of the leads. The other above-referenced prior art, U.S. Pat. No. 3,593,404 describes a similar variation except that only two different spacings are provided by means of stops and a piston and cylinder arrangement whereby the sections are moved from one set of stops to another through actuation of the piston and cylinder. Neither of these references addresses centering of the present body between the sections prior to lead severing, forming, and inserting so that lead bending can be accomplished as close as possible to the body and thus allow smaller aperture spacing in the circuit board and denser population of the components on the circuit board.
Because of the centering tolerances of the machine (not shown) for sequencing and taping these components, uncentered components must be centered prior to or during subsequent processing. Otherwise, limits must be imposed upon subsequent processing devices to prevent damage to the components. For instance, in the above-patented devices, limits are imposed upon the closeness to which the sections may be variably spaced for particular body lengths in order to ensure that one end of an uncentered body will not be damaged during the insertion operation. In an effort to overcome this problem and to ensure that leads may be bent closer to the component bodies, programs and controls have been proposed and implemented whereby the sections are opened by the lead screw, from an approximate lead spacing for a particular component, to a large enough spacing that an uncentered component body will fit between the lead formers; then the spacing is narrowed by the lead screw to engage at least one of the formers with an end of the body for better centering thereof prior to the lead severing, forming and inserting operations. This added centering step, although very accurate, has slowed the component processing by approximately 40%, a significant reduction in speed from that needed for today's production requirements.
Accordingly, a need has been demonstrated for fast, accurate centering of axial lead, electrical components such that production speeds are not significantly reduced.